title: Isotopic evidence of limited exchange between Mediterranean and eastern North Atlantic fin whales.
abstract: BACKGROUND
  The relationship between stocks of fin whales inhabiting the temperate eastern North Atlantic and the Mediterranean Sea is subject to controversy. The use of chemical markers facilitates an alternative insight into population structure and potential borders between stocks because the two areas present dissimilar isotopic baselines.
  
  
  METHODS
  Baleen plates, composed of inert tissue that keeps a permanent chronological record of the isotopic value of body circulating fluids, were used to investigate connectivity and boundaries between the stocks. Values were determined by continuous flow isotope ratio mass spectrometry.
  
  
  RESULTS
  Stable isotopes confirm that, while the two subpopulations generally forage in well-differentiated grounds, some individuals with characteristic Atlantic values do penetrate into the Mediterranean Sea up to the northernmost latitudes of the region. As a consequence, the border between the two putative subpopulations may be not as definite as previous acoustic investigations suggested. The discriminant function obtained in this study may assist researchers to use baleen plate isotopic data to assign the origin of fin whales of uncertain provenance.
  
  
  CONCLUSIONS
  This study strengthens the stock subdivision currently accepted for management and conservation while recognizes a low level of exchange between the Mediterranean and temperate eastern North Atlantic subdivisions.
authors.affiliation: Department of Animal Biology and Biodiversity Research Institute, Faculty of Biology, University of Barcelona, Av. Diagonal, 643 08071, Barcelona, Spain. joan.gimenez@csic.es
authors.forename: Joan
authors.initials: J
authors.lastname: Giménez
authors.forename: Encarna
authors.initials: E
authors.lastname: Gómez-Campos
authors.forename: Asunción
authors.initials: A
authors.lastname: Borrell
authors.forename: Luis
authors.initials: L
authors.lastname: Cardona
authors.forename: Alex
authors.initials: A
authors.lastname: Aguilar
mesh_terms: D025041:Animal Migration; D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis*; D050617:Fin Whale / Q000502:physiology*; D013058:Mass Spectrometry; D008522:Mediterranean Sea; D009587:Nitrogen Isotopes / Q000032:analysis*; D009792:Oceans and Seas
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes